A typical communications and information and communications technology (ICT) device includes power supply and distribution components (for example, a power entry module (PEM), a power module (PM), a service board, and a cooling fan). The power supply and distribution components are responsible for receiving power supply from outside of the device, and converting the power supply, input from outside of the device, to a power supply source that is applicable to loads (including the service board, the cooling fan, and the like) in the device. Generally, power supply input to a communications and ICT device includes several types: 220 volts (V) or 110 V alternating current, 48 V direct current, 240 V high voltage direct current (HVDC), and the like. Taking 220 V alternating current power supply as an example, a power supply and distribution module in a device receives 220 V alternating current input, and after completing processing, such as protective filtering, on the input power supply, converts the 220 V alternating current to a 12 V direct-current power supply source or a 48 V direct-current power supply source that is required by a back-end load.
FIG. 1 is a schematic diagram of power supply of an existing typical communications and ICT device. As shown in FIG. 1, for convenience of maintaining a communications and ICT device by operation and maintenance personnel, generally, a power supply source control switch needs to be provided on the ICT device, and the operation and maintenance personnel may perform power-on and power-off operations on the entire device by using the control switch. A position of the switch may be on a PEM, and power supply input of the device may be directly cut off by using the switch, thereby powering off the device; or the switch may be provided on a PM, so that the PM cuts off power supply output to a load by using the switch. A disadvantage of this solution is that a high-power device has a large number of power supply circuits, and a switch needs to be added to each power supply input, so that there are many power supply switches, and it is also inconvenient to perform power-on and power-off operations on the device, thereby resulting in inconvenience in powering off the device in an emergency.
FIG. 2 is a schematic diagram of power supply of an existing backup-enabled communications and ICT device. As shown in FIG. 2, to improve reliability of a power-supply system, many existing high-end communications and ICT devices support equipment-room level dual-power-source backup, where signals on N channels of power supply sources A are input to the device, and similarly, signals on N channels of power supply sources B are also input to the device; and correspondingly, PMs in the device are of N+N backup. In this way, when an input power supply source is faulty or a single PM in the device is faulty, power supply to loads (including a service broad, a cooling fan, and the like) of the entire device is not interrupted. For the N+N backup power-supply system, two control switches may be used to implement on-off control of the entire device. A connection solution of the switches is as follows: control signal A corresponding to switch A is connected to N PMs corresponding to input source A; and control signal B corresponding to switch B is connected to the other N PMs corresponding to input source B. When switch A is switched to an ON state, and the corresponding N PMs connected to control signal A detect the control signal, the N PMs separately switch on power-supply output corresponding to the power supply source (that is, implement connections between power-supply output of the power modules and the loads). When switch A is switched to an OFF state, and the corresponding N PMs connected to control signal A detect the control signal, the N PMs separately switch off the power-supply output corresponding to the power supply source (that is, cut off the connections between the power-supply output of the power modules and the loads). Similarly, switches of the N power modules corresponding to input source B can also be controlled by using switch B. Therefore, when maintenance personnel need to power on the entire device, only switch A and switch B need to be switched to the ON state; and when the maintenance personnel need to power off the entire device, only switch A and switch B need to be switched to the OFF state. A disadvantage of this solution is that power supply modules of many systems of existing communications and ICT devices are of N+m backup (where m is less than N). This switch control solution may support the foregoing N+N backup device, but is not applicable to an N+m backup system. As shown in FIG. 2, switch A controls power modules 1 to N, and switch B controls power modules N+1 to N+m. Therefore, when switch A fails or a line corresponding to control signal A is faulty, output of the power modules 1 to N may be cut off, but the remaining power modules (N+1) to (N+m) of the system are not sufficient to supply power to loads of the device (because m is less than N), thereby resulting in power-off of the entire system.